This invention relates to a system for the visualization of conformal contact between a patterned stamp and a transparent impression surface.
With the advent of printed electronics, printed photovoltaics, and printed engineered metasurfaces, there is a need to achieve feature resolutions finer than ever before in the printing industry, and to print these patterns reliably at low cost. Currently, inspection of the printing process is done in retrospect, downstream from the printing process. This approach results in a long delay between the printing and the inspection of the printed media, resulting in large amounts of scrap when the material doesn't meet specifications. In high-value printed media that uses precious ink or substrate, as with flexible electronics, waste can be quite costly. It is becoming increasingly desirable to have an inspection process that guarantees proper printing results as the point of printing and in real time.
Many common methods for contact imaging, comprising an illumination source and detector, require precise manipulation of the incident light in directionality, as is the case with total internal reflection (TIR) based methods, or control of the properties of the light, as with polarized illumination. Furthermore, the introduction of a substrate may interfere with the structuring of the illumination.
An object of the invention is therefore an imaging system for contact sensing having particular application in a roll-to-roll, continuous microcontact printing system.